be动词的用法
be （be/is/are/am/was/were)
[bi:]
vi
he is, we are, you are, they are （缩略式 I'm, you're, he's, we're, you're, they're）, （否定缩略式 I'm not, isn't, aren't）, 过去时 I was, you were, he was, we were, you were, they were （过去时否定缩略式 wasn't, weren't）,过去分词been,现在分词being
英语的“be”是个特殊动词；有些语言，如马来文等，并没有“be”这样的动词。
“Be”除了原形的“be”之外，还有另外七种形式：am, is, are, been, being, was, were.
在句子中，“be”可以是主动词(The Principal Verb)或助动词(The Auxiliary Verb)
be动词在句子中如果是“你”的话，就应该用are
“我”的话就用am
第三人称“它”“他”“她”是用Is
这个变化规则其实是没有什么根据的，就是一种语句方法罢了。
英语其实变化规则挺多的，遇见不好记的，尽量编一个顺口溜，既方便又好记
备注提示1：be动词还有was，were，being，been，to be
备注提示2：如果是一般过去时,就用was/were，如果是一般现在时,就用am/is/are，如果是一般将来时,就用will be
备注提示3：一般过去时：第一人称和第三人称的单数形式，则用was，第一人称和第二人称、第三人称的复数，则用were
备注提示4：一般现在时：第一人称单数形式，用am，第三人称单数形式，用is，第一人称复数、第二人称、第三人称的复数形式，则用are
备注提示5：一般将来时：will be句式：顺口溜（刚刚讲到的）：一般时态有关be动词的口诀：我用am，你用are，is连着他她它，单数主语用is，复数主语全用are
备注提示6：当“be”要在祈使句中出现时，陈述句可借助助动词“do”，否定句必须在前加上助动词“don't”，如：
Don't be silly!
Do be obedient!
Be careful!
Don'tbe a fool!
备注提示7：Be + 现在分词”以组成进行式时态(Continuous Tenses)，如：
Tony's maidis washing his new car.
The children are playing in the field.
Samuel was eating when I came in.
We have been living here since 1959.
备注提示8：事/物人 +Be + 过去分词”以组成被动语态(The Passive Voice),如：
Her money in the drawer was stolen
A number of good jobs are taken up by foreigners
David studied in Taiwan but hasbeen trained as a language lecturer in America
Can all the wonderful birds be found in our Bird Park
The disobedient boywas told to stand out- side the classroom
Steps are being taken to reduce traffic con- gestion during peak hours
Dishonest students will be immediately dealt with
You are...
He/She/It is...
We/They are....(我们we和他们they在复数范围里)
其余单词如果是单数，就用is,如果是复数，就用are.
A cat is...
Two cats are...
具体的使用情况因时态语态而异：
eg:I am a boy.
eg:I was a boy at that time.
eg:Three years later, I will be a teacher.
eg：He/She is an Englishman/Englishwoman.
eg:He/She was playing soccer ball at 4 pm.
eg:He/She was a teacher,but now he/she is a bank clerk.
eg:We are family.
eg:We were watching TV at that moment.
eg;We will be a teacher two years later.
